As functional elements in the electric/electronic field or the optical field, there is known an electroluminescent device capable of emitting light by applying a voltage. In general, this electroluminescent element can be roughly classified into an inorganic electroluminescent element using an inorganic electroluminescent material for a light-emitting layer (hereinafter referred to as “inorganic EL element”) and an organic electroluminescent element using an organic electroluminescent material for a light-emitting layer (hereinafter referred to as “organic EL element”).
In comparison with the organic EL element, the inorganic EL device is hard to cause light emission with high luminance, it has an advantage that not only it is excellent in long-term stability, but it stably causes light-emission even under a severe condition such as a high temperature. For that reason, in order to utilize it in fields where weather resistance, heat resistance, long-term stability, or the like is required, studies regarding the inorganic EL element are being continued.
Also, the inorganic EL element enables a device to be formed on paper or a polymer film by a printing technique, and it forms a market as an illumination device in which flexibility is required. As such an inorganic EL element, there is known an electroluminescent element in which an insulating layer and a light-emitting layer are formed on a back-side electrode, a transparent electrode is provided thereon, and the top and bottom thereof are covered with a hygroscopic film. The light-emitting layer is printed by means of screen printing or the like (see, for example, Patent Document 1). However, such a technique requires a lot of manufacturing processes. For that reason, as a method capable of achieving mass production, there is known a method of inexpensively manufacturing an inorganic EL element by means of roll printing and lamination (see, for example, Patent Document 2).